What is an efficient way to remove loose vertices?
In some instances, depending on topology, the following can work:


Select one of the vertices that you want to remove.


Choose Select> Similar> Amount of Connecting Edges from the 3D view header.


Deselect any vertices that have been selected but that you don't want to delete (in this case, the corners) and choose Mesh> Delete> Dissolve Vertices to delete the unwanted vertices.